Re: [PATCH] ksmbd: fix leak of transform buffer on encrypt_resp() failure

On Tue, Nov 4, 2025 at 11:12 PM Qianchang Zhao pioooooooooip@gmail.com wrote:

When encrypt_resp() fails at the send path, we only set STATUS_DATA_ERROR but leave the transform buffer allocated (work->tr_buf in this tree). Repeating this path leaks kernel memory and can lead to OOM (DoS) when encryption is required.

Reproduced on: Linux v6.18-rc2 (self-built test kernel)

Fix by freeing the transform buffer and forcing plaintext error reply.

Reported-by: Qianchang Zhao pioooooooooip@gmail.com Reported-by: Zhitong Liu liuzhitong1993@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Qianchang Zhao pioooooooooip@gmail.com

---

fs/smb/server/server.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/smb/server/server.c b/fs/smb/server/server.c index 40420544c..15dd13e76 100644 --- a/fs/smb/server/server.c +++ b/fs/smb/server/server.c @@ -244,8 +244,14 @@ static void __handle_ksmbd_work(struct ksmbd_work *work, if (work->sess && work->sess->enc && work->encrypted && conn->ops->encrypt_resp) { rc = conn->ops->encrypt_resp(work);

•           if (rc < 0)
  

•           if (rc < 0) {
                    conn->ops->set_rsp_status(work, STATUS_DATA_ERROR);
  

•                   work->encrypted = false;
  

•                   if (work->tr_buf) {
  

•                           kvfree(work->tr_buf);
  

->tr_buf is freed in ksmbd_free_work_struct(). How can tr_buf not be freed? Thanks.

•                           work->tr_buf = NULL;
  

•                   }
  

•           }
    }
    if (work->sess)
            ksmbd_user_session_put(work->sess);
  

-- 2.34.1